Ethan Yonker | bd7492d | 2016-12-07 13:55:01 -0600 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2016 The Team Win Recovery Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "Decrypt.h" |
| 18 | #include "Ext4Crypt.h" |
| 19 | |
| 20 | #include <string> |
| 21 | |
| 22 | #include <errno.h> |
| 23 | #include <stdio.h> |
| 24 | #include <sys/stat.h> |
| 25 | #include <sys/types.h> |
| 26 | |
| 27 | #include "ext4_crypt.h" |
| 28 | #include "key_control.h" |
| 29 | |
| 30 | #include <hardware/gatekeeper.h> |
| 31 | #include "HashPassword.h" |
| 32 | |
| 33 | #include <android-base/file.h> |
| 34 | |
| 35 | int gatekeeper_device_initialize(gatekeeper_device_t **dev) { |
| 36 | int ret; |
| 37 | const hw_module_t *mod; |
| 38 | ret = hw_get_module_by_class(GATEKEEPER_HARDWARE_MODULE_ID, NULL, &mod); |
| 39 | |
| 40 | if (ret!=0) { |
| 41 | printf("failed to get hw module\n"); |
| 42 | return ret; |
| 43 | } |
| 44 | |
| 45 | ret = gatekeeper_open(mod, dev); |
| 46 | |
| 47 | if (ret!=0) |
| 48 | printf("failed to open gatekeeper\n"); |
| 49 | return ret; |
| 50 | } |
| 51 | |
| 52 | int Get_Password_Type(const userid_t user_id, std::string& filename) { |
| 53 | std::string path; |
| 54 | if (user_id == 0) { |
| 55 | path = "/data/system/"; |
| 56 | } else { |
| 57 | char user_id_str[5]; |
| 58 | sprintf(user_id_str, "%i", user_id); |
| 59 | path = "/data/system/users/"; |
| 60 | path += user_id_str; |
| 61 | path += "/"; |
| 62 | } |
| 63 | filename = path + "gatekeeper.password.key"; |
| 64 | struct stat st; |
| 65 | if (stat(filename.c_str(), &st) == 0 && st.st_size > 0) |
| 66 | return 1; |
| 67 | filename = path + "gatekeeper.pattern.key"; |
| 68 | if (stat(filename.c_str(), &st) == 0 && st.st_size > 0) |
| 69 | return 2; |
| 70 | printf("Unable to locate gatekeeper password file '%s'\n", filename.c_str()); |
| 71 | filename = ""; |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | bool Decrypt_DE() { |
| 76 | if (!e4crypt_initialize_global_de()) { // this deals with the overarching device encryption |
| 77 | printf("e4crypt_initialize_global_de returned fail\n"); |
| 78 | return false; |
| 79 | } |
| 80 | if (!e4crypt_init_user0()) { |
| 81 | printf("e4crypt_init_user0 returned fail\n"); |
| 82 | return false; |
| 83 | } |
| 84 | return true; |
| 85 | } |
| 86 | |
| 87 | bool Decrypt_User(const userid_t user_id, const std::string& Password) { |
| 88 | uint8_t *auth_token; |
| 89 | uint32_t auth_token_len; |
| 90 | int ret; |
| 91 | |
| 92 | struct stat st; |
| 93 | if (user_id > 9999) { |
| 94 | printf("user_id is too big\n"); |
| 95 | return false; |
| 96 | } |
| 97 | std::string filename; |
| 98 | bool Default_Password = (Password == "!"); |
| 99 | if (Get_Password_Type(user_id, filename) == 0 && !Default_Password) { |
| 100 | printf("Unknown password type\n"); |
| 101 | return false; |
| 102 | } |
| 103 | int flags = FLAG_STORAGE_DE; |
| 104 | if (user_id == 0) |
| 105 | flags = FLAG_STORAGE_DE; |
| 106 | else |
| 107 | flags = FLAG_STORAGE_CE; |
| 108 | gatekeeper_device_t *device; |
| 109 | ret = gatekeeper_device_initialize(&device); |
| 110 | if (Default_Password) { |
| 111 | if (!e4crypt_unlock_user_key(user_id, 0, "!", "!")) { |
| 112 | printf("e4crypt_unlock_user_key returned fail\n"); |
| 113 | return false; |
| 114 | } |
| 115 | if (!e4crypt_prepare_user_storage(nullptr, user_id, 0, flags)) { |
| 116 | printf("failed to e4crypt_prepare_user_storage\n"); |
| 117 | return false; |
| 118 | } |
| 119 | printf("Decrypted Successfully!\n"); |
| 120 | return true; |
| 121 | } |
| 122 | if (ret!=0) |
| 123 | return false; |
| 124 | printf("password filename is '%s'\n", filename.c_str()); |
| 125 | if (stat(filename.c_str(), &st) != 0) { |
| 126 | printf("error stat'ing key file: %s\n", strerror(errno)); |
| 127 | return false; |
| 128 | } |
| 129 | std::string handle; |
| 130 | if (!android::base::ReadFileToString(filename, &handle)) { |
| 131 | printf("Failed to read '%s'\n", filename.c_str()); |
| 132 | return false; |
| 133 | } |
| 134 | bool should_reenroll; |
| 135 | ret = device->verify(device, user_id, 0, (const uint8_t *)handle.c_str(), st.st_size, |
| 136 | (const uint8_t *)Password.c_str(), (uint32_t)Password.size(), &auth_token, &auth_token_len, |
| 137 | &should_reenroll); |
| 138 | if (ret !=0) { |
| 139 | printf("failed to verify\n"); |
| 140 | return false; |
| 141 | } |
| 142 | char token_hex[(auth_token_len*2)+1]; |
| 143 | token_hex[(auth_token_len*2)] = 0; |
| 144 | uint32_t i; |
| 145 | for (i=0;i<auth_token_len;i++) { |
| 146 | sprintf(&token_hex[2*i], "%02X", auth_token[i]); |
| 147 | } |
| 148 | // The secret is "Android FBE credential hash" plus appended 0x00 to reach 128 bytes then append the user's password then feed that to sha512sum |
| 149 | std::string secret = HashPassword(Password); |
| 150 | if (!e4crypt_unlock_user_key(user_id, 0, token_hex, secret.c_str())) { |
| 151 | printf("e4crypt_unlock_user_key returned fail\n"); |
| 152 | return false; |
| 153 | } |
| 154 | if (!e4crypt_prepare_user_storage(nullptr, user_id, 0, flags)) { |
| 155 | printf("failed to e4crypt_prepare_user_storage\n"); |
| 156 | return false; |
| 157 | } |
| 158 | printf("Decrypted Successfully!\n"); |
| 159 | return true; |
| 160 | } |